GAINESVILLE, Ga. -- Four men accused of plotting to attack U.S. government agents with explosives and toxins were denied bond Wednesday.

The men's bond hearing began Tuesday in federal court where prosecutors played recordings of them talking about attacking government officials with explosives, weapons and the deadly biological toxin ricin.

The defendant never intended to follow through and were actually working to unite various militia factions to serve the state of Georgia, a defense attorney said Tuesday.

Frederick Thomas, 73, and Dan Roberts, 67, are accused of conspiring to obtain an explosive and possessing an unregistered silencer. Ray Adams, 55, and Samuel Crump, 68, are charged with conspiring and attempting to make ricin.

They pleaded not guilty at a court hearing last week, the same day prosecutors revealed that one of the men talked of targeting U.S. Attorney General Eric Holder and former U.S. Rep. Cynthia McKinney. Authorities also said Thomas, described as the ringleader, had stockpiled 52 guns and 30,000 rounds of ammunition at his home in the Georgia mountains.

Defense attorney Jeff Ertel, who represents Thomas, said the recordings were taken out of context. He said other conversations show the men talked of uniting various militia groups scattered across Georgia to become "the governor's army." He said the men talked of teaching courses in First Aid and even gardening to attract members and legitimize the movement.

Ertel also attacked the credibility of the confidential informant who recorded the conversations. He said the informant has had a series of legal troubles, including two recent charges of child pornography and child molestation that involved a 13-year-old and a 15-year-old.

Assistant U.S. Attorney Robert McBurney said the informant first contacted FBI agents in July 2010 after he was charged in South Carolina with child molestation and child pornography. The charges are still pending, but the informant has been released from jail on bond.

McBurney said the informant failed a polygraph about the details of the alleged plot in 2010 but that he later contacted the FBI again and was sent to a March meeting between Thomas, Roberts and several other men. He recorded Thomas at that gathering speaking of targeting "enemies of the Constitution" with weapons and explosives.

He also played aloud another tape where Thomas talked of attacking "civilian government operatives" with the FBI and other government agencies. Roberts was heard telling the group to "do whatever it takes" and Adams said on the tape: "The first ones that need to die are the ones in the government buildings."

Some family members of the suspects quietly shook their as the tapes played Tuesday.

At last week's hearing, defense attorneys indicated they were too elderly and infirm to carry out the attacks. Ertel said his client was just making boastful talk that he never intended to act upon. And Thomas' wife, Charlotte, testified her husband was a great-grandfather who suffered from heart disease, emphysema and other illnesses.

"He loves his country," she said of the U.S. Navy veteran. "He's the most patriotic man I've ever met."

But prosecutors dismissed claims that the men are too old to have executed the alleged plot. McBurney said the men took concrete steps toward carrying out the mission, including casing federal buildings in Atlanta, trying to buy a briefcase explosive that could be detonated by cellphone, attempting to make the toxin ricin and amassing the weapons cache.

The four allegedly boasted of a list of government officials who needed to be "taken out;" talked about scattering ricin from a plane or a car speeding down a highway past major U.S. cities; and scouted tax offices, with one man saying, "We'd have to blow the whole building like Timothy McVeigh," a reference to the man executed for bombing a federal building in Oklahoma City in 1995.

Federal investigators said they had the men under surveillance for at least seven months, using an undercover informant to infiltrate their meetings at a Waffle House, homes and other places, before finally arresting them in early November. The arrests came just days after authorities say they discovered evidence they were trying to extract ricin from castor beans.